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World's Largest Ocean Thermal Power Plant Planned For China
cylonlover writes "Lockheed Martin has been getting its feet wet in the renewable energy game for some time. In the 1970s it helped build the world's first successful floating Ocean Thermal Energy Conversion (OTEC) system that generated net power, and in 2009 it was awarded a contract to develop an OTEC pilot plant in Hawaii. That project has apparently been canceled but the company has now shifted its OTEC sights westward by teaming up with Hong Kong-based Reignwood Group to co-develop a 10 MW pilot plant that will be built off the coast of southern China."
This is ridiculous, the length limit algorithm needs to be updated, these jackoffs are breaking it somehow, I shouldn't have to hold Page Down for 2 seconds to skip past one comment.
This system requires deep water. The deeper the better. Think over a mile deep.
It will likely be quite a distance off shore. And unlike a windmill, it doesn't have to be 300' high.
In Stockholm, Sweden we have since many years been running the worlds largest heat pump facility, 225 MW. http://sv.wikipedia.org/wiki/Hammarbyverket.
It's using waste water from a nearby waste water treatment facility that serves a large fraction of the Stockholm metropolitan area of some 2M people.
The shortest way from Hawaii to China is to go west.
it's one of the features of a sphere.
Maybe I missed it but the picture gives me a vague impression that waves have something to do with it but I didn't see them mentioned? I suppose the water movement wouldn't be much use though.
No, it has nothing to do with waves. It uses the ocean's thermal gradient as a power source: because there is warm water on top, and cold on the bottom, we can use the difference to generate power (much like heat from a conventional power plant). Keep in mind it won't be very efficient, since the temperature difference is relatively low, but since you have quite a lot of seawater to utilize, efficiency isn't terribly important.
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
OTEC isn't a serious contender for green energy. It sounds good because it seems to combine romantic elements of green energy: limitless sea water, temperature gradients with huge thermal sinking ability, minimal environmental impact, etc. The truth of the matter is that OTEC has serious fundamental limitations, the worst of which is the fact that economically viable energy output requires enormous amounts of water flow - beyond what is capable with modern technology. Pulling an ultra-high flow water column from deep enough in the ocean to create a good thermal differential from surface water requires enormous pipes, which current materials technology can't deliver - because the tensile strength of even the strongest materials would buckle under the weight of the pipes themselves. Heat exchanges have to be very efficient, and sea life/creatures easily clog up the internals of the heat exchangers, so conformal coatings have to be developed to allow good thermal transfer while preventing the accumulation of bio. Finally, it just can't compete with simple proven solutions like hydro-electric. Look at any company that bids on OTEC and you'll see that the real funding vessels are in conformal coatings, materials technology, and pump technology, among other things. I don't forsee anyone building a viable OTEC plant for the purpose of commercial energy production anytime soon.
This system requires deep water. The deeper the better. Think over a mile deep.
Seawater at that depth is rich in nutrients. Ocean thermal plants could be combined with aquaculture to make them more cost effective. After the water is drawn up and warmed in the heat exchanger, it is released at the surface. The nutrients result in a plankton bloom that can be eaten by fish, shrimp, oysters, etc.
Damn China. Who the hell do those people think they are? A forward project that is not absolutely guaranteed to return a profit, although it may be a key to future energy production. They'll probably blithely say that although this approach might not work, try a few of them and there's a good shot at finding at least one winner. And that winner could be worth a fortune and be essential to our future. Damn China, it acts like mid-20th century America. Any good libertarian or fiscal conservative can tell you how badly this country turned out after they wasted all that government money.
Kinetic energy of water is 0.5*mv^2. For 1 ton of water moving 1 m/s, that's 500 joules per ton. If it's moving at 5 m/s (about the max you'll see in tidal areas), that's 12.5 kJ/ton.
Water has a specific heat of 4.2 kJ/kg*C. If there's a 1 degree temperature differential, that's 4.2 MJ per ton. You have to go a bit deep to get to colder water, but by about 1km down it's around 4 C. So relative to tropical surface water, you're talking about a 25 degree difference, or an energy potential of 100 MJ per ton. Nearly 5 orders of magnitude more per ton than the kinetic energy in tidal currents.
The catch being that it's much more difficult to extract power from temperature differentials than it is from kinetic energy. If it were easy, every car engine would have a stirling engine alongside it to extract energy from the waste heat. But stirling engines generate so little power per mass of the engine that it's more efficient just to forgo the additional weight and dump the waste heat via a radiator.
Back before we became a bunch of short-sighted corporatists who laugh at anything that doesn't turn a profit in one quarter.
I swear to God...I swear to God! That is NOT how you treat your human!
If it works China will use the partnership to steal any useful technology, produce it themselves and out compete Lockheed. See partnerships with high speed train manufacturers and solar cell production.
Because China has such a stellar environmental record.
No, and I can give you a mile long list of serious complaints about the Chinese government, in terms of both their domestic and foreign affairs. But give the devil his due. At least they're trying something here. You know, kind of like the United States once had the guts to do?
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If there's a 1 degree temperature differential, that's 4.2 MJ per ton.
The catch being that it's much more difficult to extract power from temperature differentials than it is from kinetic energy. If it were easy, every car engine would have a stirling engine alongside it to extract energy from the waste heat. But stirling engines generate so little power per mass of the engine that it's more efficient just to forgo the additional weight and dump the waste heat via a radiator.
It's not just "more difficult", it's scientifically impossible to capture all of the power from temperature differentials. The maximum possible efficiency of such a heat engine is described by Carnot's Theorem and is (1-Tc/Th) where Tc and Th are the absolute temperatures of the cold and hot reservoir. So if 100MJ of heat flows from a hot water reservoir into a cold water reservoir through a heat engine you can only capture a single digit percentage of that energy for the temperature differences under discussion
So taking a 25 degree heat difference as 275K cold water and 300K hot water then the optimum efficiency of the heat enginer is only 8.3%, and the actual efficiency will of course be less.